1. Field of the Invention
The present invention relates to a sliding type lens cover apparatus for camera, and more particularly, to a lever-driven sliding type lens cover apparatus for camera.
2. Description of the Related Arts
In photography, the quality of an image is generally dependent on the film in the conventional camera or the CCD in the digital camera, and the lens. However, physical damages, such as flaws and scars, caused by undesired or accidental contact of the lens by a rigid object, and contaminations caused by dirt, grease, and fingerprints, often make problems in the maintenance of the lens, which seriously affects the quality of the image. It is thus very important to protect the lens in doing maintenance of the camera. In practice, lens covers are often adopted to protect the lens.
The conventional lens covers can be divided into two types: clipping type covers and mechanical type covers.
The clipping type cover is a disc-like device, and usually has a pair of clips to releasably engage with the lens barrels to fix the cover in front of the lens. Most of the clipping type covers are separate parts, independent of the cameras, and are usually tied to the cameras with strings to avoid being lost. These covers are very common in the conventional cameras, but not used so often in the digital camera industry.
The mechanical type covers can be divided into motor-driven type covers and hand-driven type covers. Both types employ mechanics to selectively open/close the cover and thus exposing/shielding the lens. U.S. Pat. No. 5,913,089 (the '089 patent) and U.S. Pat. No. 6,254,289 (the '289 patent) respectively describe a lens barrel cover of this type. The two similar inventions are both based on the same theory, which enables an element with short moment arm (such as the barrier driving lever in the '089 patent and the power gear in the '289 patent) to drive another element with long moment arm (such as the main-barrier cover and the sub-barrier cover in the '289 patent and the lens cover in the '089 patent). However, according to the lever principle, in order to work an element with long moment arm, the element with short moment arm needs a large force. Thus, such conventional designs bring in difficulty in operation.
Hence, an improved lens cover apparatus for camera is required to overcome the disadvantages of the prior art.